Device for the cooling or heating of objects arranged on a specimen carrier



June 11, 1968 GRASENlcK ET AL 3,388,251

DEVICE FOR THE COOLING OR HEATING OF OBJECTS ARRANGED ON A SPECIMEN CARRIER Filed June 29, 1964 2 Sheets-Sheet l ill .rrzvevzipns' 5" F Grasenwk By \S. Gessvzer I June 11, 1968 GRASENlCK ET AL 3,388,251

DEVICE FOR THE COOLING OR HEATING OF OBJECTS ARRANGED ON A SPECIMEN CARRIER Filed June 29, 1964 2 Sheets-Sheet United States Patent 4 Claims. (01. 250-495 The invention relates to a device for the cooling or heating of objects arranged on a specimen carrier, particularly of preparations used in electronic microscopy, wherein the specimen plate comprising a stem is axially displaceable, if necessary, tiltable and rotatable about its axis.

A conventional cooling device comprises a cylindrical, double-jacketed vessel receiving the coolant and inserted in the treatment chamber, closed on top by means of an annular cover presenting a tubular extension protruding into the interior of the cooling chamber, the surface of said extension being surrounded by a cooled body consisting of ring segments resting on one side on the surface of said extension while being displaceable axially against the action of a spring on the other side. For cooling purposes, the specimen plate can be moved close to the said cooling body in heat-conducting communication with the coolant via the annular cover of the cooling chamber. The specimen plate is provided with an electric heating element for the occasional heating of the specimen plate. Where objects have to be alternatingly heated and cooled, the high degree of thermal inertia of the heating element is an objectionable feature. Moreover, the power supply. to the spatially displaceable specimen plate presents considerable difficulties. Furthermore, the convention device comprises a large number of component parts requiring relatively high precision machining, making their manufacture comparatively costly. During the cooling of the specimen plate, heat abduction from the specimen plate to the coolant is impaired by the use of mobile intermediate elements and the surface contact between the cooling body and the specimen plate required to ensure uniform heat transfer is no longer assured when the specimen plate is inclined, however slightly.

It is the purpose of the present invention to overcome these shortcomings of conventional cooling devices by the provision of a specimen carrier which can be moved close to a cooling body in heat-conducting communication with the coolant and/or a heated body and is elastically connected with its shaft so as to permit of limited axial displacement of the specimen carrier in relation to the said stem as well as of inclination of the said specimen carrier about an axis of tilt situated in the plane of the carrier for the purpose of moving the said carrier into operative association with the cooling and/ or heated body. This design provides for positive application of the specimen carrier close to the cooling and/or heated against said body under a uniform pressure over the entire periphery of said carrier, so as to obtain the largest possible contact area, thereby ensuring positive heat transfer from the carrier to the cooling body and/ or from the heated body to the carrier. Moeover, the absence of mobile parts in the device as hereinabove described alone facilitates the transfer of heat. Moderate inclination of the specimen carrier in relation to the contact surface of the cooling and/or heated body before contact with said contact surface is established, will not have any adverse effect as the articulated elastic connection between the carrier and the stem compensates the sloping position in the cooling and/or heating phase.

According to a preferred feature of the invention, the stem comprises a flange at its carrier end, said fiange seiz- 3,383,251 Patented June 11', 1968 ice ing a fastening ring inserted in a cylindrical recess on the underside of the carrier loosely from behind, a helical compression spring engaging in the underside of the carrier being provided in a concentrical stepped-down bore of the shaft. This particularly simple design is not only inexpensive to manufacture but also advantageous in view of the cooling or heating effect thereby achieved. The concentric action of the spring on the plate ensures uniformity of pressure applied to contact surfaces over the entire preiphery of the carrier even if the latter assumes an inclined position, provided the same does not exceed the tilting range of the plate toward the shaft.

In addition, the carrier and the shaft are in contact with each other alongside narrow bearing surfaces only, so that the specimen carrier is the chief beneficiary of the cooling and/or heating effect and will quickly take on the desired temperature.

Finally, in yet another embodiment of the invention, the shaft comprises a flange at its carrier end, said flange engaging in a fastening ring inserted in a cylindrical recess on the underside of the carrier with a clearance, a star-shaped spring, an annular corrugated spring or the like clamping element being provided in the recess between the annular fiange and the carrier. This design affords further simplification of the manufacturing process as no spiral guiding or bearing surfaces will be required for the springs used in this embodiment of the invention.

Further details of the invention will appear from the following description of several embodiments of the invention restricted to a cooling device, with reference to the accompanying drawing in which:

FIG. 1 shows a sectional view through the longitudinal axis of the device according to the invention,

FIG. 2 is a section through a detail on the line IIII of FIG. 1,

FIGS. 3 and 4 each showing an axial cross-sectional view of an example of the specimen carrier according to the invention,

FIG. 5 is a top view of the embodiment shown in FIG. 4 with the specimen carrier removed.

In the embodiment shown, a cylindrical cooling jacket 1 is provided, e.g. inside a treatment chamber (not shown), which can be designed, for example, as a container serving to produce a vacuum, said cooling jacket being closed on top by a ring 2 and enclosing the specimen carrier 7. The specimen carrier 7 is mounted on a tilting platform 3 in such a manner as to be rotatable around an axis extending in perpendicular relation to its plane, the tilting platform 3 carrying the specimen carrier 7 being pivoted on a supporting frame 4 and rotatable around an axis extending in parallel relation to the plane of the specimen carrier 7. The specimen carrier 7 and the central part of the tilting platform 3 are shown in elevation in FIG. 1.

The supporting frame 4 comprises two horseshoe-shaped ring segments 17 and 18 superjacent in spaced relation to each other, and interconnected at their open ends by brackets S and 5 respectively and on their closed end by another bracket 19.

The supporting frame 4 is mounted on slide bars 20, 20' traversing the bracket 19 and maintained in position at their upper extremities by means of a ring 21 in such a manner as to be shiftable in the longitudinal direction of the device. The ring 21 is further supported by columns 22, 22' provided outside the supporting frame 4. The supporting frame 4 is displaced by means of a threaded spindle 23 rotatably mounted with its upper extremity in the ring 21, the said spindle traversing the bracket 19 and co-operating with a female thread 24 provided in same. For the swiveling of the tilted platform 3 a grooved shaft 25 traversing the bracket 5 is provided,

whereas the specimen carrier 7 is rotated by another grooved shaft 25 traversing the bracket 5 and operating the specimen carrier 7 via shaft 26.

Within the area of displacement of the specimen carrier 7 a cooled body is provided, comprising a tube 6 extending through the ring 21 of the holder and the horseshoeshaped ring segment 17 as far as the area of the supporting frame 4, the said tube presenting a flange 27 at its upper extremity, said flange being mounted on the ring 2 of the cooling jacket 1.

In order to achieve uniform application of the specimen carrier 7 against the cooling body 6, the specimen carrier 7 is elastically connected with its stem 8 presenting a flange 9 at its carrier end, said flange seizing a fastening ring 11 screwed into a cylindrical recess on the underside of the plate 7 and provided with blind bores for the insertion of a wrench, loosely from behind. In the embodiment shown in FIG. 2, the stem 8 is provided with a concentrical stepped-down bore 12 in which a helical compression spring 13 is inserted, the lower extremity of which rests on the shoulder of the bore 12, while its other extremity acts on a projection on the underside of the carrier 7. A tubular sleeve 16 tops the shaft 8.

In the embodiment illustrated in FIGS. 4 and 5, a starshaped spring 14 is located in the cylindrical recess 10 between the flange 9 and the specimen carrier 7, the bent-up spring arms of which act on the underside of the carrier 7, whereas the central area of the spiral spring 14 is elastically applied against the flange 9 of the stem 8.

In both embodiments of the invention the opposite surfaces of the flange 9 and of the carrier 7 are located in spaced relation to each other in such a manner that the carrier '7 is free to perform in relation to the stem 8 both a limited axial motion and a tilting motion about an axis of tilt extending in perpendicular relation to the axis of the carrier. FIG. 3 indicates the maximum tilt of the stem 8 possible in relation to the plate 7 as shown by the dotted line illustrating the tilt of the flange 9.

The limited axial displaceability and tiltability of the specimen carrier in relation to the stem 8 permits positive application of the carrier 7 against the tube 6 thus ensuring efficient and rapid cooling or heating of the specimen carrier 7, as the case may be.

A number of different variants are feasible within the scope of the invention in addition to the embodiments of the invention hereabove described, such as by providing instead of the cooling body or in addition to same, a heated body, such as a heated ring arranged in concentrical relation to the cooling body and axially displaceable, said ring being moved close to the specimen plate for the purpose of heating the latter. Likewise, it would be possible to arrange the cooling body and the heated body opposite each other, the plate being brought into contact with any of these bodies in its topmost or bottommost position, as the case may be. For example, a plurality of compression springs distributed over the periphery of the flange 9 for the purpose of producing the pressure required for the application of the plate 7 to the cooling body or to the heated body, or flexible Washers made of rubber or the like could be substituted for the 4- springst Furthermore, the flange 9 itself could constitute the spring means, the carrier being secured to it at the outer periphery.

We claim:

1. A device for the cooling or heating of articles, particularly of preparations used in electron microscopy, in a treatment chamber, comprising a specimen carrier to receive the article to be treated, means for displacing, tilting and rotating the said specimen carrier about an axis thereof, at least one body having a temperature diflerent from that of the said specimen carrier which may be brought into a heat conductive contact with the said body, and a stern elastically connected with the specimen carrier on the side of the specimen carrier facing away from the surface carrying the article thus to thereby permit a limited amount of axial displacement and inclination of the specimen carrier in relation to the said stem for the purpose of achieving uniformity of the heat-conductive contact between the specimen carrier and the said body.

2. A device according to claim 1, in which the specimen carrier has a cylindrical recess on the side carrying the said stem, and in which a fastening ring is provided inserted in said recess, said stem having a flange at the extremity thereof facing the specimen carrier, said flange being arranged in the said recess of the specimen carrier between the latter and the said fastening ring, the outside diameter of the said flange being larger than the internal diameter of the said fastening ring, and in which a prestressed spring is provided between the said specimen carrier and the stem.

3. A device according to claim 2, in which a concentric stepped-down bore is provided in the said stem, and in which a helical compression spring is provided resting with one of its extremities in the said bore of the stem and with its other extremity on the side of the said specimen carrier carrying the said stem.

4. A device according to claim 1, in which the specimen carrier has a cylindrical recess on the side carrying the said stem, and in which a fastening ring is provided inserted in said recess, said stem having a flange at the extremity thereof facing the specimen carrier, said flange being arranged in the said recess of the specimen carrier between the latter and the said fastening ring, the outside diameter of the said flange being larger than the internal diameter of the said fastening ring, and in which a prestressed spring is provided between the said specimen carrier and the stem, said prestressed spring consisting of a star-shape arranged in the said recess of the specimen carrier between the latter and the said flange.

References Cited UNITED STATES PATENTS 7/1964 Busch et al. 25049.5 2/1965 Busch et a1. 250-495 ARCHIE R. BORCHELT, RALPH G. NILSON,

Examiners. 

1. A DEVICE FOR THE COOLING OR HEATING OF ARTICLES, PARTICULARLY OF PREPARATIONS USED IN ELECTRON MICROSCOPY, IN A TREATMENT CHAMBER, COMPRISING A SPECIMENT CARRIER TO RECEIVE THE ARTICLE TO BE TREATED, MEANS FOR DISPLACING, TILTING AND ROTATING THE SAID SPECIMEN CARRIER ABOUT AN AXIS THEREOF, AT LEAST ONE BODY HAVING A TEMPERATURE DIFFERENT FROM THAT OF THE SAID SPECIMEN CARRIER WHICH MAY BE BROUGHT INTO A HEAT CONDUCTIVE CONTACT WITH THE SAID BODY, AND A STEM ELASTICALLY CONNECTED WITH THE SPECIMEN CARRIER ON THE SIDE OF THE SPECIMEN CARRIER FACING AWAY FROM THE SURFACE CARRYING THE ARTICLE THUS TO THEREBY PERMIT A LIMITED AMOUNT OF AXIAL DISPLACEMENT AND INCLINATION OF THE SPECIMEN CARRIER IN RELATION TO THE SAID STEM FOR THE PURPOSE OF ACHIEVING UNIFORMITY OF THE HEAT-CONDUCTIVE CONTACT BETWEEN THE SPECIMEN CARRIER AND THE SAID BODY. 